Method of giving printing-rolls deprived of their etching or engraving their original diameter.



P. E. PRBSOHLIN. METHOD OF GIVING PRINTING ROLLS DEPRIVED OF THEIRBTCHING 0R ENGRAVING THEIR ORIGINAL DIAMETER. APPLIOATION FILED JULY 11,1910.

lll'. I I I PAUL ERNST rnEsoHLrN. or SGHLADERN-ON-THE-SIEG, GERMANY.

METHOD OF GIVING PRINTING-ROLLS DEPRIVED OF THEIR ETCHING 0R ENGRAVINGTHEIR ORIGINAL DIAMETER.

Specification of Letters Patent.

PatentedOct. 10, 1911.

Application filed July 11, 1910. Serial No. 571,369.

To all whom it may concern:

Be it known that I, PAUL ERNST Pnnsoir LIN, a subject of the Emperor ofGermany, and resident of Schladern-on-the-Sieg, Germany, have invented anew and useful Method for Giving PrintingRolls Deprived of Their Etchingor Engraving Their Original Diameter, of which the following is aspecification. V

Heretofore it was usual to employ printing rolls, which had been reducedin diame: ter by cutting orturning away the engraving or etching, thathad to be done to about twice the depth of the incisions or corrosionscreated by engraving or etching. The rolls thus reduced in diametercould not be used for designsor pictures of the same size, but had to beemployed for other printing purposes for instance for designs of smallersize.

fabrics, because it becomes necessary to replace the rolls by new oneseven though they have been reduced only a few millimeters, so that alarge number of spare rolls had to be kept on stock. The reduction inthe size of the roll after each refacing is however of specialinconvenience in rotatable printing machines for news-papers, becausehereit is indispensable to retain the form or the circumference of theprinting rolls of acertain size. Heretofore, when it was desired to givethe rolls deprived of the skin containing the engraving or etching theiroriginal diameter there was only one very expensive way known and thatis the enlarging of the roll by electrome-tallurgy. p

These drawbacks are done away with by the present invention in this way,that the roll to be renewed, which generally consists of a mantle ofcopper having an ironor steel core is first loosened on its core,preferably after depriving it of its engravings or etchings, by exertinga pressure progressingly on the outer surfacewhereby the diameter of themantle at the same time is increased. Hereupon the core is taken out andthe copper mantle is driven on a new core of a larger size and thendrawn together with this new core through a matrixring of such diameteras to press the enlar ed mantle tight against the core and to bring itat the same time to the desired diameter.

This drawback is seriously felt when; making use of printing rolls forprinting The loosening of the mantle on the old core is carried onpreferably by aid of rollers, in a kind of rollin mill.

A rolling mill of this description is illustrated in Figure 1 of theaccompanying drawings in end View, the roll operated upon being shown insection. Fig. 2 shows an enlarged mantle half way pressed down on a coreby aid of a matrix-ring. Figs. 3, 4 and 5 show a mantle on threedifferent cores of increasing diameter on which it is successivelyplaced after each renewal.

The mill shown in Fig; 1 consists of a frame aon which two'rollers b arejournaled. Pivoted to the upper part of the frame a are two levers einwhich a third or pressure roller 03 is journaled. Eye-bolts f arepivoted to the lower part of the frame under the outer ends of thelevers e. These eyebolts are threaded on their upper part and adapted toproject through the ends of the levers e, which for this purpose arebifurcated or provided with a longitudinal slot not seen in the drawing.A nut or internally threaded hand-wheel f is screwed on the threadedportion of each eye-bolt and when screwed down presses against the lever6.

When the mantle of a printing roll is to be enlarged and loosened on itscore,.the roll a is placed on rollers b and the roller (5. is thenpressed down upon it by aid of the levers d and the nuts P, which whenproperly tightened exert a pressure on the levers e to firmly pressthe'roller d down on the roll 0. By rotating the rolls 6, which can bedone by any desired means not shown in the drawing, the roll 0 and alsothe roller "d is rotated and the progressing pressure thus acting on theroll 0 serves to loosen the mantle c on its core g and to enlarge itsdiameter. When this is done in a sufiicient manner, the mantle c isdrawn oil the core 9 and slipped over anew core g of a larger diameterand then drawn through a matrix ring 2', Fig. 2, of such diameter topress down themantle to the size, which it had, before the engravings'oretchingswere removed. In thus pressing down the mantle snugly clings tothe new core. Printing rolls or mantles can be treated repeatedly inthis manner, whereby on every renewal a core g g Figs. 3, 4, 5 of acorrespondingly larger (liameter is chosen, while the rollitself'constantly is brought back to its original diameter D. 'Thismethod may be repeated so often as the thickness of the mantle 0.willallow, which can be made of copper or any other metal suited to beengraved or etched.

If desired the removing of the skin containing the engraving or etchingcan be car ried on after the mantle is pressed on a new core instead ofbefore loosening it on the old one. 1

I claim:

1. The method of restoring the original diameter to a printing rollcomposed of a core and mantle and deprived of its etching or engraving,which consistsin exerting a progressing pressure'on the circumference ofthe roll, thereby enlarging the diameter of the mantle and loosening itfrom the core, slipping the loose mantle onto a core of larger diameter,and afiixing the mantle onto the core by drawing the core and mantlethrough a matrix ring.

2. The method of enlarging a print-ingroll composed of a core having aremovable man-. tle, which consists in exerting a progressing pressureon the circumference of the roll, thereby enlarging the diameter of themantle and loosening it from the core, placing the loosened mantlearound a core of larger diameter than the original core, and afiixingthe mantle onto the larger core.

3. The method of restoring a reduced 30 printing roll, composed of acore having a removable mantle, to its original diameter, which consistsin rotating the roller, subjecting the mantle to pressure during therotation,-thereby enlarging the diameter of mantle, rotating the rollerbetween pressure rolls to enlarge the diameter of the mantle therebyloosening the latter from the core, removing said core from the mantle,inserting a core of larger diameter than the removed core into theenlarged mantle, and

passing the latter with the enlarged core through amatrix ring theinterior diameter of which'is the same as the diameter of the originaletched roll.

PAUL ERNST PRESCHLIN.

Witnesses:

LOUIS VANDORY,

Bns'srn F. DUNLAP.

